| 摘要 |
PURPOSE:To smoothly extrude a synthetic resin extruded article consisting of a substantially non-foamed rigid outer skin in its inner surface and outer surface and having a hollow foamed cross section. CONSTITUTION:A narrow part 6 is provided on the connection part between the mandrel 4 of an extrusion mold 2 and the inner mold 5 of a forming die 3, and onto the enlargement of a flow conduit resulted therefrom, foamable resin is allowed to foam in order to relax the foaming strength, thereby rendering the fluidity of the resin smooth, and further by the reduction of heat transfer through the reduction of the cross-sectional area in the connection part, the effective cooling in the inner mold of the forming die is carried out, whereby a non-foamed rigid skin layer is formed even in the inner surface of an article. |
